Sublimation protection coating for thermoelectric materials and devices

Protective coating to prevent sublimation are disclosed. More particularly, the protective coatings comprise one or more alkaline earth halide materials, or mixtures thereof, to prevent sublimation. The alkaline earth halide material of the coating can be judiciously selected to match the coefficient of thermal expansion (CTE) of the material of the external surface of the underlying substrate coated. The protective coatings may be advantageous for protecting external surfaces of thermoelectric materials, parts and devices at high temperature to prevent sublimation and material loss.